CCST Project

Fumigant Use in California and an Assessment of Available Alternatives

Overview

Responding to a request from the California Department of Pesticide Regulation (DPR), CCST will conduct a review of current fumigant use in California and a comprehensive assessment of available alternatives to these fumigants. Broadly, a fumigant is a volatile or volatilizable chemical compound used as a pesticide. Fumigants can be used as an insecticide, fungicide, disinfectant, nematicide, herbicide, and even a rodenticide. They can be applied in a wide variety of settings such as in the home, in structures, healthcare and food facilities, for crop growth and management, and to control vector-borne or animal-borne diseases.

Phase I Release

Across two phases, the study will assess:

The present state of fumigant use in California (including ways to mitigate emissions for post-harvest applications)
Currently available alternatives for these fumigants and the extent of their use
Past and on-going research dedicated to fumigant alternatives
Viability of adopting these alternatives to effectively manage pests in California
Barriers to wide-scale adoption of alternatives
Areas where research may still be needed to answer some of these questions

Although fumigants are used in a variety of settings, the study will focus on three uses of fumigants: pre-plant soil fumigation, post-harvest commodity fumigation, and structural fumigation.

Fumigants covered in the study will be limited to:

Agricultural pre-plant soil fumigants
- 1,3-dichloropropene (1,3-D)
- Chloropicrin
- Dazomet
- Metam-Sodium
- Potassium N-Methyldithiocarbamate (Metam-potassium)
- Methyl bromide

Post-harvest commodity fumigants
- Sulfuryl Fluoride
- Phosphine
- Propylene oxide
- Methyl bromide

Structural fumigants
- Sulfuryl Fluoride

CCST is conducting this study across two phases. The Phase I report, completed in February 2025, focuses exclusively on the pre-plant soil fumigants 1,3-D and chloropicrin and their alternatives.

Work is currently underway on Phase II, which has an expanded scope that includes the four remaining pre-plant soil fumigants as well as the fumigants used for treating post-harvest commodities and structures. The Phase II report is expected to be completed by Fall of 2025.

CCST is seeking nominations of individuals with relevant expertise to serve in various roles in support of this study, such as report monitors, peer reviewers, and subject matter experts. Please submit names, affiliations, relevant areas of expertise and contact information for individuals who are qualified to serve in support of this study. Self-nominations are welcome.